1. Field of the Invention
The subject invention relates generally to a method for forming finished workparts from a continuous strip of sheet-metal, and more particularly to an improved method for forming finished workparts utilizing a transfer die-type punch press machine.
2. Description of the Prior Art
Punch press operations are frequently used in manufacturing processes to form a sheet-metal workpart into a final workpart shape. It is often necessary to form the workpart into final shape using a series of successive forming operations. When the workpart is large and/or is to be formed into a complex shape, a transfer die-type punch press is typically employed having a series of successive forming stations disposed along an axial path along which individual disconnected workparts progress from one forming station to successive forming stations. After a part has been formed at one station, fingers of a transfer mechanism pick the part up and transfer it to successive forming stations for further forming until the desired final shape is achieved. It is well known in the sheet-metal forming industry to blank workparts from the sheet-metal strip in staggered, close-nested fashion to minimize material waste. Examples of such teachings are illustrated in the U.S. Pat. Nos. 745,505 to Lee, issued Dec. 1, 1903; 915,043 to Robinson, issued Mar. 9, 1909; 3,665,794 to Wiig, issued May 30, 1972; 3,785,231 to Lake, Jr. et al, issued Jan, 15, 1974; and 3,786,704 to Lachaussee et al, issued Jan. 22, 1974.
After the workparts are blanked from the strip in the above manner, the practice currently known in the industry is to transfer the blanked workparts from the blanking station to a separate punch press machine where they are positioned along the axial path of the punch press for further transfer from one forming station to the next by the transfer mechanism of the punch press.